Full-Depth Reclamation Using a Cement Slurry Spreader Attached to a Ready Mixed Concrete Truck W....
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Transcript of Full-Depth Reclamation Using a Cement Slurry Spreader Attached to a Ready Mixed Concrete Truck W....
Full-Depth ReclamationUsing a Cement Slurry Spreader Attached to aReady Mixed Concrete Truck
W. Spencer Guthrie, Ph.D., Associate ProfessorCharles A. Hope, EIT, Graduate Research Assistant
Department of Civil and Environmental Engineering, Brigham Young University
ASCE Infrastructure Report Card
Water Content
Cem
ent
Co
nte
nt
Cast
Rolled
No Wearing Course RequiredWearing Course Required
Roller-Compacted Concrete
Conventional Concrete
Soil-Cement
Flowable Fill
Cement-Modified Soil
Full-DepthReclamation
Cement-Treated Base
Cement-Based Pavement Materials
PerviousConcrete
Definition ofFull-Depth Reclamation (FDR)
“…technique in which the full flexible pavement section and a
predetermined portion of the underlying materials are uniformly crushed, pulverized, or blended,
resulting in a stabilized base course; further stabilization may be obtained through the use of
available additives.” - Asphalt Recycling and Reclaiming Association
FDR is most appropriate under the following conditions:
■ The pavement is seriously damaged and cannot be rehabilitated with simple resurfacing.
■ The existing pavement distress indicates that the problem likely exists in the base or subgrade.
■ The existing pavement distress requires full-depth patching over more than 15 to 20 percent of the surface area.
■ The pavement structure is inadequate for the current or future traffic.
• Uses in-place materials• Requires little or no
material to be hauled off• Maintains or improves
existing grade• Conserves virgin material• Saves cost by using
in-place “investment”• Saves energy by reducing
mining and hauls• Is a very sustainable
process
Advantages of the FDR Process
Benefits of FDR Using Cement
• Increased rigidityfor distributing loads• Elimination of rutting below surface• Reduced moisture and frost susceptibility• Reduced fatigue cracking• Thinner pavement sections
Rehabilitation Strategies
Attribute
Rehabilitation Strategy
Reclamation with Cement
Structural Overlay
Removal and Replacement
New pavement structure
Fast construction X
Minimal traffic disruption X X
Minimal material in/out X X
Conservation of resources X XMaintenance of existing elevation X
Low cost X X
Pulverize, Shape, Add Cement, Mix In Place, Compact, and Surface
GranularBase
Subgrade
Existingroad
Bituminous Surfacing
Subgrade
Pulverized
Pulverizationto desired
depth
Subgrade
Pulverized
Removal ofexcess
material (if necessary)and shaping
Subgrade
Stabilized
Addition of cement, mixing,
reshaping, and compacting
Subgrade
Stabilized
New Surfacing
Application of final surface
course
FDR Construction Process
Pulverization
Reshaping
Cement Spreading
Cement Spreading
Cement Uniformity
Material Blending
Compaction
Grading
Curing
Minimal Disruption
Microcracking
Microcracking
Surfacing
• Service Life = 20 years• Design Equivalent Single Axle Loads =
15,000• Overall Standard Deviation = 0.45• Initial Serviceability = 4.5• Terminal Serviceability = 2.0• Asphalt Structural Layer Coefficient =
0.40• Cement-Treated Base Structural Layer
Coefficient = 0.18• Drainage Coefficient = 1.0• Subgrade Resilient Modulus = 15 ksi
New Surfacing
Subgrade
8 in. CTB
3 in. HMA
Final Pavement Structure
Pavement Analysis
Cost = 20% Less than Traditional Reconstruction
Reliability = 99.99%
Summary
• FDR with cement stabilization provides a durable structural layer with many engineering, environmental, and economic benefits
• Cement can be applied on urban projects with a slurry spreader attachment to ensure uniformity and eliminate all fugitive dust
Thank You!